Casting thin strip and delivery nozzle therefor

Abstract

A method of casting metal strip and equipment therefor where an elongated metal delivery nozzle extending along in a continuous caster with at least one segment having a main portion adapted to deliver molten metal in the casting pool above the nip along the metal delivery nozzle and an end portion adjacent side dams having a reservoir portion with first and second pairs of passages adapted to deliver molten metal into a molten metal pool adjacent the side dams while shells are forming on the casting rolls. The first pair of passages adapted to deliver molten metal into the casting pool adjacent the side dams, and the second pair of passages adapted to deliver molten metal into the casting pool adjacent the molten metal from the first pair of passages adjacent the side dams to inhibit formation of skulls during the formation of the cast strip during a casting campaign.

1 . A method of casting metal strip comprising:
 (a) assembling a pair of casting rolls laterally disposed to form a nip between them and between side dams adapted to maintain a molten metal pool supported by the casting rolls,   (b) assembling an elongated metal delivery nozzle extending along and above the nip with at least one segment having a main portion adapted to deliver molten metal in the casting pool along the metal delivery nozzle and an end portion adjacent each side dam having a reservoir portion having a first pair and a second pair of passages adapted to deliver molten metal into a molten metal pool adjacent the side dams while shells are forming on the casting rolls, the first pair of passages adapted to deliver molten metal into the casting pool adjacent the side dams and the second pairs of passages adapted to deliver molten metal into the casting pool adjacent molten metal delivered from the first pair of passages,   (c) introducing molten metal through the elongated metal delivery nozzle to form a casting pool of molten metal supported on the casting rolls above the nip, and through the first and second pairs of passages in the reservoir portion in the end portions into the casting pool, and   (d) counter rotating the casting rolls to deliver cast strip downwardly from the nip.   
     
     
         2 . The method of casting metal strip as claimed in  claim 1  having the first pair of passages and the second pair of passages such that the first and second pairs of passages are adapted to deliver molten metal outwardly from the reservoir portion of the delivery nozzle toward the side dam. 
     
     
         3 . The method of casting metal strip as claimed in  claim 1  where the second pair of passages is spaced longitudinally inward of first pair of passages in the reservoir portion, the direction of flow from the first and second pairs of passages directed to below the reservoir portion. 
     
     
         4 . The method of casting metal strip as claimed in  claim 1  where the second pair of passages is spaced laterally inward of the first pair of passages in the reservoir portion, the direction of flow from each pair of passages directed to converge below the reservoir portion. 
     
     
         5 . The method of casting metal strip as claimed in  claim 3  where the direction of flow from each of the first and second pairs of passages converge. 
     
     
         6 . The method of casting metal strip as claimed in  claim 4  where the direction of flow from each of the first and second pairs of passages converge. 
     
     
         7 . The method of casting metal strip as claimed in  claim 3  where the direction of flow from each of the first and second pairs of passages are substantially parallel. 
     
     
         8 . The method of casting metal strip as claimed in  claim 4  where the direction of flow from each of the first and second pairs of passages are substantially parallel. 
     
     
         9 . The method of casting metal strip as claimed in  claim 3  where the direction of flows from the first and second pairs of passages are directed toward the side dam. 
     
     
         10 . The method of casting metal strip as claimed in  claim 4  where the direction of flows from the first and second pairs of passages are directed toward the side dam. 
     
     
         11 . The method of casting metal strip as claimed in  claim 3  where the reservoir portion having a central passage adapted to deliver molten metal downwardly to the casting pool under the reservoir portion. 
     
     
         12 . The method of casting metal strip as claimed in  claim 4  where the reservoir portion having a central passage adapted to deliver molten metal downwardly to the casting pool under the reservoir portion. 
     
     
         13 . The method of casting metal strip as claimed in  claim 11  where the direction of flow from the central passage is downwardly toward the side dam. 
     
     
         14 . The method of casting metal strip as claimed in  claim 12  where the direction of flow from the central passage is downwardly toward the side dam. 
     
     
         15 . The method of casting metal strip as claimed in  claim 11  where the central passage having a diameter of between 4 mm and 8 mm. 
     
     
         16 . The method of casting metal strip as claimed in  claim 12  where the central passage having a diameter of between 4 mm and 8 mm. 
     
     
         17 . The method of casting metal strip as claimed in  claim 3  where the direction of flow from first pair of passages is different from the direction of flow from the second pair of passages. 
     
     
         18 . The method of casting metal strip as claimed in  claim 4  where the direction of flow from first pair of passages is different from the direction of flow from the second pair of passages. 
     
     
         19 . The method of casting metal strip as claimed in  claim 1  where the first and second pairs of passages have the same diameter. 
     
     
         20 . The method of casting metal strip as claimed in  claim 1  where the first and second pairs of passages have diameters of between 6 mm and 14 mm. 
     
     
         21 . The method of casting metal strip as claimed in  claim 1  where the first pair of passages has a cross-section smaller than a cross-section of the second pair of passages. 
     
     
         22 . The method of casting metal strip as claimed in  claim 1  where the first and second pairs of passages of the reservoir portion are shaped to control the velocity of molten metal through the passages. 
     
     
         23 . The method of casting metal strip as claimed in  claim 1  where the reservoir portion in the end portion of each segment has longitudinally extending weirs adjacent the side walls of the inner trough adapted to allow molten metal to flow over the weirs between the reservoir portion and the main portion. 
     
     
         24 . A metal delivery apparatus for casting metal strip comprising:
 at least one elongated segment having a main portion adapted to deliver molten metal in the casting pool along the metal delivery nozzle; and,   an end portion adjacent side dams having a reservoir portion having first and second pairs of passages adapted to deliver molten metal into a molten metal pool adjacent the side dams while shells form on the casting rolls, the first pair of passages adapted to deliver molten metal into the casting pool adjacent the side dams and the second pair of passages adapted to deliver molten metal into the casting pool adjacent molten metal delivered from the first pair of passages.   
     
     
         25 . The metal delivery apparatus for casting metal strip as claimed in  claim 24  having the first pair of passages and the second pair of passages such that the first and second pairs of passages are adapted to deliver molten metal outwardly from the reservoir portion of the delivery nozzle toward the side dam. 
     
     
         26 . The metal delivery apparatus for casting metal strip as claimed in  claim 24  where the second pair of passages is spaced longitudinally inward of the first pair of passages in the reservoir portion, the direction of flow from the first and second pairs of passages directed to below the reservoir portion. 
     
     
         27 . The metal delivery apparatus for casting metal strip as claimed in  claim 24  where the second pair of passages is spaced laterally inward of the first pair of passages in the reservoir portion, the direction of flow from the first and second pairs of passages directed to below the reservoir portion. 
     
     
         28 . The metal delivery apparatus for casting metal strip as claimed in  claim 26  where the direction of flow from each of the first and second pairs of passages converge. 
     
     
         29 . The metal delivery apparatus for casting metal strip as claimed in  claim 27  where the direction of flow from each of the first and second pairs of passages converge. 
     
     
         30 . The metal delivery apparatus for casting metal strip as claimed in  claim 26  where the direction of flow from each of the first and second pairs of passages are substantially parallel. 
     
     
         31 . The metal delivery apparatus for casting metal strip as claimed in  claim 27  where the direction of flow from each of the first and second pairs of passages are substantially parallel. 
     
     
         32 . The metal delivery apparatus for casting metal strip as claimed in  claim 26  where the direction of flow from each of the first and second pairs of passages are directed toward the side dam. 
     
     
         33 . The metal delivery apparatus for casting metal strip as claimed in  claim 27  where the direction of flow from each of the first and second pairs of passages are directed toward the side dam. 
     
     
         34 . The metal delivery apparatus for casting metal strip as claimed in  claim 26  where the reservoir portion having a central passage adapted to deliver molten metal downwardly to the casting pool under the reservoir portion. 
     
     
         35 . The metal delivery apparatus for casting metal strip as claimed in  claim 27  where the reservoir portion having a central passage adapted to deliver molten metal downwardly to the casting pool under the reservoir portion. 
     
     
         36 . The metal delivery apparatus for casting metal strip as claimed in  claim 34  where the direction of flow from the central passage is downwardly toward the side dam. 
     
     
         37 . The metal delivery apparatus for casting metal strip as claimed in  claim 35  where the direction of flow from the central passage is downwardly toward the side dam. 
     
     
         38 . The metal delivery apparatus for casting metal strip as claimed in  claim 34  where the central passage having a diameter of between 4 mm and 8 mm. 
     
     
         39 . The metal delivery apparatus for casting metal strip as claimed in  claim 35  where the central passage having a diameter of between 4 mm and 8 mm. 
     
     
         40 . The metal delivery apparatus for casting metal strip as claimed in  claim 26  where the direction of flow from the first pair of passages is different than the direction of flow from the second pair of passages. 
     
     
         41 . The metal delivery apparatus for casting metal strip as claimed in  claim 27  where the direction of flow from the first pair of passages is different than the direction of flow from the second pair of passages. 
     
     
         42 . The metal delivery apparatus for casting metal strip as claimed in  claim 24  where the first and second pairs of passages have the same diameter. 
     
     
         43 . The metal delivery apparatus for casting metal strip as claimed in  claim 24  where the first and second pairs of passages have diameters of between 6 mm and 14 mm. 
     
     
         44 . The metal delivery apparatus for casting metal strip as claimed in  claim 24  where the first pair of passages has a cross-section smaller than a cross-section of the second pair of passages. 
     
     
         45 . The metal delivery apparatus for casting metal strip as claimed in  claim 24  where the first and second passages of the reservoir portion are shaped to control the velocity of molten metal through the passages. 
     
     
         46 . The metal delivery apparatus for casting metal strip as claimed in  claim 24  where the reservoir portion in the end portion of each segment has longitudinally extending weirs adjacent the side walls of the inner trough adapted to allow molten metal to flow over the weirs between the reservoir portion and the main portion of the metal delivery apparatus.